[SciPy-user] Thin plates for a 3D deformation field
Sat Oct 27 18:01:57 CDT 2007
I don't know of any fast multipole solver or anything fancy like that
for dealing with evaluating the splines rapidly, but for simple
purposes, the rbf module in scipy.sandbox should do just fine.
Set the function to 'thin-plate', and you will get a thin-plate
spline interpolator that can interpolate values of arbitrary
dimension in spaces of arbitrary dimension. So it should naturally be
able to interpolate a 3D deformation field in three dimensions, or
any other combination you might want.
I haven't used the RBF module exclusively (I wrote my own thin-plate
spline interpolator before it existed -- it's a very small amount of
code), but I think that that module should be just right. One note:
this sort of interpolation can be very slow if you're going to be
interpolating the deformations over a fine grid -- for, say, using
the deformation field for image warping. This is where one might
start wanting a fast multipole solver. I find that in most cases, I
can get away with interpolating the deformations on a relatively
coarse grid, and then using linear interpolation to fill in the gaps.
(The resizing methods in ndimage come in useful here -- just scale up
the x, y, and z components of the deformation separately.)
On Oct 26, 2007, at 4:35 AM, Matthieu Brucher wrote:
> I wondered if someone knew of a package that allows the
> interpolation of a 3D deformation field with thin plates (or in
> fact with anything) based on a list of points and their associated
> deformation field.
> If only 2D deformation field is supported by a package, I'll go for
> it too ;)
> French PhD student
> Website : http://miles.developpez.com/
> Blogs : http://matt.eifelle.com and http://blog.developpez.com/?
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